1. Field of the Invention
This invention is in the field of chemical agents and methods of inhibiting infection of cells by retrovirus.
2. Description of the Prior Art
Integrins represent a family of cell surface .alpha..beta. heterodimeric proteins that mediate cell adhesion to other cells and to extracellular matrix constituents including fibronectin (FN). Integrins composed of .beta.1 and .beta.3 subunits complexed to .alpha.3, .alpha..sub.v and .alpha..sub.5 subunits interact with the arginyl-glycyl-aspartic acid (RGD) sequence of FN7 whereas .alpha.4.beta.1 is specific for RGD-independent sequences in the carboxyl terminal cell and heparin-binding domain of fibronectin that mediates cell attachment. However, recent evidence suggests that cellular recognition and adhesion to fibronectin domains is more complex, involving not only integrins, but also cell surface proteoglycans (PG). PG are complex macromolecules consisting of a core protein to which highly anionic glycosaminoglycan (GAG) chains are covalently attached by an O-linkage to serine or threonine residues. The anionic properties of GAG on many cell surface PG are important for binding to their respective ligands. Clearly, cell interactions with FN may involve several distinct sites, and this has been shown by the use of synthetic FN peptides. Cell binding to an A-chain-derived 33 kD carboxyl terminal heparin binding fragment of human plasma fibronectin or 66KD B chain may involve both cell surface .alpha.4.beta.1 integrin and PG since this FN fragment contains cationic peptides, which bind cell surface chondrortin and heparin proteoglycans (CSPG and HSPG respectively) and/or alpha and beta integrans directly. FIG. 1 shows a schematic diagram depicting the location of the 33 kD carboxyl terminal heparin binding fragment within fibronectin and the synthetic peptides described in this application. In contrast to peptides FN 1-5 and FN7, which are present within type III homologies common to all isoforms of fibronectin, peptide FN6 is restricted to isoforms of fibronectin which contain the type IIIcs region (A-chains of human plasma fibronectin and human cellular or "tissue" fibronectin). The amino terminal end and the carboxyl terminal limit of the 33 kD fragment is based on known sequence dam. Selected biological domains, indicated in FIG. 1 by roman numerals at the top of the figure, are based on the nomenclature of Furcht, 1981. I=weak heparin binding, II=collagen binding (noncovalent), III=free sulfhydryl, IV=RGD-mediated cell adhesion, V=carboxyl terminal strong heparin binding and cell adhesion, VI=free sulfhydryl. Approximate locations of tryptic (T) and cathepsin D (C) sites on intact fibronectin are shown. The .alpha.4.beta.1 integrin also binds to VCAM, which is an Ig superfamily receptor expressed on certain cells, including activated endothelial cells. Sequences of fibronectin peptides may interfere with alpha 4 beta VCAM dependent interactions or other integrin, selectin or CAM dependent interations.
Human immunodeficiency virus type 1 (HIV-1), a retrovirus, is the etiologic cause of AIDS. The HIV-1 envelope glycoprotein, gp120, binds to the CD4 receptor on T lymphocytes and on mononuclear phagocytes leading to infection of these target populations. Although infection of T lymphocytes requires cellular proliferation and DNA synthesis, productive infection of monocytes can occur independently of cellular DNA synthesis. Moreover, infection of activated CD4 + lymphocytes causes cell death, whereas infected monocytes are relatively resistant to destruction by the virus, serving as long-lived reservoirs of HIV.. These cells not only provide a source of replicating virus, but their dysfunction following infection may contribute to increased susceptibility to opportunistic infections that are the hallmark of AIDS. Because monocyte-macrophages serve as reservoirs for HIV-1, selective targeting of this population, in addition to T lymphocytes, needs to be considered.
Zidovudine (AZT), an analogue of thymidine, dideoxyinosine (ddi), and dideoxycytosinene, dideoxycytosine (ddc) are the primary anti-viral drugs currently in use for the treatment of HIV infection. These agents inhibit viral replication, but are unable to eliminate the virus. In addition, bone marrow toxicity, loss of efficacy with time and emergence of resistant HIV strains with available therapies have necessitated continued exploration for alternative drugs for the treatment of HIV infection. We have recently identified a novel mechanism for inhibiting HIV infection utilizing fibronectin and/or its fragments which provide the basis for therapeutic intervention. There is an extensive body of literature related to AIDS research.
Furcht, L. T. 1981, Structure and Function of the adhesive Glycoprotein Fibronectin Mod. Cell Biol. 53-117.
Finberg, R. W., Wahl, S. M., Allen, J. B., Soreart, G., Strom, T. B., Murphy, J. R., and Nichols, J. C. 1991. Selective elimination of HIV-1 infected cells using an IL-2 receptor specific cytotoxin Science. 252:1703-1705.
Fischl, M. A., et al.: 1987. New Engl. J.Med. 317:185-191.
Hildreth, J. E. K., Orentas, R. J.: 1989. Involvement of a leukocyte adhesion receptor (LFA-1) in HIV-induced syncytium formation. Science 244:1075-1078.
Kalter, D. C., Gendelman, H. E., Meltzer, M. S.: 1991. Inhibition of human immunodeficiency virus infection in monocytes by monoclonal antibodies against leukocyte adhesion molecules. Immunol Lett. 30:219-227.
Pantaleo, G., Butini, L., Graziosi, C., Poli, G., Schmittman, S. M.: 1991. Human immunodeficiency virus (HIV) infection in CD4+ T-lymphocytes genetically deficient in LFA-1; HIV-1 is required for HIV-mediated cell fusion but not for viral transmission. J.Exp. Med. 173:511-514.
Pluda, J. M., Yarchoan, R., McAtee, N., Smith, P. D., Thomas, R., Oette, D., Maha, M., Wahl, S. M., Myers, C., and Broder, S., 1990. A feasibility study using an alternating regiment of azidothymidine (AZT) and recombinant granulocyte-macrophage colony stimulating factor (GM-CSF) in patients with severe human immunodeficiency virus (HIV) infection and leukopenia. Blood. 76:463-472.
Rosenberg, Z. F. and Fauci, A. S. 1991. Immunopathogenesis of HIV infection. FASEB J. 5:2382.
Szebeni, J., Wahl, S. M., Schinazi, R. F., Popovic, M., Gartner, S., Wahl, L. M., Weislow, O. S., Betageri, G., Fine, R. L., Dahlberg, J. E., Hunter, B. and Weinstein, J. N.: 1990. Dipyridamole potentiates the activity of zidovudine and other dideoxynucleosides against HIV-1 in cultured cells. Annals of New York Academy of Sciences. 626:613-616.
Szebeni, J., Wahl, S. M., Wahl L. M., Gartner, S., Popovic, M., Parker, R., Black, C. D., and Weinstein, J. N.: 1990. Inhibition of HIV-1 in monocyte/macrophage cultures by 2',3'-dideoxycytidine-5'-triphosphate, free and in liposomes. AIDS Research and Human Retroviruses. 6:691-702.
Valentin, A., Lundin, K., Patarroyo, M., Asjo, B.: 1990b. The leukocyte adhesion glycoprotein, CD18, participates in HIV-1 induced syncytia formation in monocytoid cells and T-cells. 1. Exp. Med. 173:511-514.
Wahl, S. M., Allen, J. B., McCartney-Francis, N. Morganti-Kossmann, M. C., Kossmann, T., Ellingsworth, L., Mergenhagen, S. E., and Orenstein, J. M.: 1991. Transforming growth factor beta. A potential macrophage and astrocyte-derived mediator of CNS dysfunction in AIDS. Journal of Experimental Medicine. 173:89 1-899.
Wahl, S. M., Allen, J. B., Gartner, S., Orenstein, J. M., Chenoweth, D. E., Popovic, M., Arthur, L. O., Farrar, W. L., and Wahl, L. M.: 1989. Human immunodeficiency virus and its envelope glycoprotein down-regulate chemotactic ligand receptors and chemotactic function of peripheral blood monocytes. Journal of Immunology. 142:3553-3559.
Weinstein, J. N., Bunow, B., Welslow, O. S., Schinazi, R. F., Wahl, S. M., Wahl, L. M., and Szebeni, J.: 1991. Synergistic drug combinations in AIDS therapy: Dipyridamole-azidothymidine in particular and principles of analysis in general. Annals of New York Academy of Sciences. 616:367-384.
Albelda, S. M. and Buck, C. A. 1990. Integrins and other cell adhesion molecules. FASEB J. 4, 2668-2680.
Haugen, P. K., McCarthy, J. B., Skubitz, A. P. N., Furcht, L. T. and Letourneau, P. C. 1990. Recognition of the A-chain carboxyl-terminal heparin-binding region of fibronectin involves multiple sites: two contiguous sequences act independently to promote neural cell adhesion. J. Cell Biol. 111:2733-2745.
McCarthy, J. B., Mickelson, D. L., Chelberg, M. K. and Furcht, L. T. 1988. Localization and chemical synthesis of fibronectin peptides with melanoma adhesion and heparin-binding activities. Biochemistry 27:1380-1388.
Ruoslahti, E. 1991. Integrins. J. Clin. Invest. 87:1-5.
Springer, T. 1990. Adhesion receptors of the immune system. Nature 346:425-434.
Verfaile, C. M., McCarthy, J. B. and MeGlave, P. B. 1991. Differentiation of primitive human multipotent hematopoietic progenitors into single-lineage clonogenic progenitors is accompanied by alterations in their interaction with fibronectin. J. Exp. Med. 174:693-703.
Wahl, L. M., Katona, I. M., Wilder, R. L., Winter, C. C., Haraoui, B., Scher, I. and Wahl, S. M. 1984. Isolation of human mononuclear cell subsets by counterflow centrifugal elution. Characterization of .beta.-lymphocytes, T-lymphocytes and monocyte-enriched fractions by flow cytometric analysis. Cell. Immunol. 85:373.
Wilke, M. S., Skubitz, A. P. N., Furcht, L. T. and McCarthy, J. B. 1991. Human keratinocytes adhere to two distinct heparin-binding synthetic peptides derived from fibronectin. J. Invest. Derm. 97:573-579.
Su et at., Mol. Immunology, August 1991, 28(8):811-817 describe the binding of fibronectin to gp 120.